Rotor of electric motor for compressor

Abstract

At least three axis direction through-holes arranged at equal intervals in the circumferential direction are provided in a rotor laminated steel plate and a rotor end plate. The rotor laminated steel plate and the rotor end plate are fixed with three rivets for passing through the axis direction through-holes. A balance weight formed of one laminated metal plate is fixed to the one rotor end plate with two rivets of the three rivets. A balance weight formed of the other laminated metal plate is integrated by caulking and has a projection formed thereon and fixed to the other rotor end plate with the remaining single rivet. The projection is engaged with a recess or a through-hole provided in the other rotor end plate so that the balance weight is positioned to the other rotor end plate.

The invention claimed is: 
     
       1. A rotor of an electric motor for a compressor comprising:
 a rotor laminated steel plate; 
 a permanent magnet configured to be provided in the rotor laminated steel plate and to be arranged to form a plurality of magnetic poles in a circumferential direction around a rotation axis; 
 rotor end plates configured to be provided on both end surfaces of the rotor laminated steel plate and to restrict movement of the permanent magnet in an axis direction; and balance weights configured to be formed of laminated metal plates respectively fixed to outer surfaces of the rotor end plates, wherein 
 at least three axis direction through-holes arranged at equal angle intervals in the circumferential direction are provided in the rotor laminated steel plate and the rotor end plates, 
 the rotor laminated steel plate and the rotor end plates are fixed with three rivets for passing through the axis direction through-holes, 
 one of the balance weights formed of one laminated metal plate is fixed to one of the rotor end plates with the two rivets of the three rivets, 
 a projection having an outer diameter D 3  is formed on the other balance weight formed of the other laminated metal plate which is integrated by caulking, and the other balance weight is fixed to the other rotor end plate with the remaining single rivet, and 
 the projection is engaged with a recess or a through-hole, the recess or the through-hole being provided in the other rotor end plate and having an inner diameter D 4  greater than the outer diameter D 3  of the projection, so that the balance weight is positioned to the other rotor end plate. 
 
     
     
       2. The rotor of an electric motor for a compressor according to  claim 1 , wherein the electric motor is a six-pole electric motor. 
     
     
       3. The rotor of an electric motor for a compressor according to  claim 1 , wherein a material of the balance weight is a nonmagnetic material.